Flashlights and other portable illumination devices are very useful devices that include an illumination source as part of an electrical circuit incorporating one or more batteries (to supply current to the illumination source) and a switch to complete or interrupt the circuit. Typically, manually operated mechanical switches which have been designed for the mechanical sturdiness have been used as flashlight switches, such as the switch disclosed in U.S. Pat. No. 4,286,311 (granted Aug. 25, 1981 to Maglica), which is hereby incorporated in its entirety by reference. The function of a switch in previously available flashlights has been limited to completing or interrupting the electrical circuit to the illumination source.
The switch used in the '311 patent is a push-button switch featuring a rotary contact, which is rotated axially when the button is depressed, “wiping” across stationary contacts that complete the circuit with the lamp and the batteries, in order to clean those surfaces. This is done to overcome the problems of oxidation and buildup of dirt on the electrical contacts, occurrences which increase electrical resistance in the circuit and thus undesirably limit the current flow to the illumination source.
As a result, the previously available switches require that the switch be activated with enough force to clean the contacts and rotate, or otherwise move cleaning components. The previously available flashlights using such switches thus require an amount of force large enough to provide the “wiping” effect. A MAGLITE® flashlight, believed to be a market embodiment of the device represented in the '311 patent, requires a mass of over 1270 grams to latch the '311 type-switch closed when the weight was applied to the pushbutton on the flashlight until the switch was triggered. Moreover, the '311 type-switch had a stroke distance of over 5 mm to the latching position. This large force and long stroke distance may be difficult for a person with small hands to use while grasping the flashlight, or a person with reduced hand strength, as from an arthritic hand condition.
It is commonly accepted in the industry as true that the large amount of force and distance required to operate the switch, and the audible “click” that accompanies its function, may also serve as a way to prevent the switch from being accidentally operated, as inside a backpack, or toolbox.
Additionally, a switch structure like that shown in the '311 patent provides simply a way for the circuit of the flashlight to open and close, it does not provide a structure by which additional electrically based functions can be easily added to the flashlight.
It is noteworthy that none of the known prior art provides a portable illumination device with a switch that requires very little force to operate, or a short stroke distance to operate, or a switch which combines the features of needing little force to operate or needing a short stroke distance to operate, with the ability to integrate additional electronic functions within the switch structure.
The available art is thus characterized by several disadvantages that are addressed by the present invention. The present invention minimizes, and in some aspects eliminates, the above-mentioned shortcomings and other problems, by utilizing the methods and structural features described herein.